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In this we are going to this discuss on the resultant features of river erosion

Answer Text:
Resultant Features of River Erosion
1. Stream Cut Valleys
- Valleys with V, open V or U shaped cross sections along the river channel.

- In the source region a river cuts itself a channel which starts as a gulley.
- The channel is deepened by vertical erosion resulting into a -shaped valley.
- In the middle stage lateral erosion widens and deepens the valley resulting in a more open v-cross section.
- In the old stage lateral erosion creates a very wide channel with a U-shaped cross section.

2. Gorges
- Narrow, deep, steep-sided valley.
Ways/modes of formation
a) Where a river flows along a fault or a section of soft rocks eroding the channel vertically through the soft rocks or fault.
b) By headward erosion at a water fall when the river’s erosive activity is increased due to increased gradient causing
the river to undercut at the base of the water fall, then the rock above the undercut base collapses causing the waterfall
to shift upstream resulting in a gorge below the water fall.
c) Where a river flows across a plateau with alternating horizontal layers of hard and soft rocks eroding them resulting in a gorge with
stepped sides called a canyon e.g. Grand canyon on R. Colorado in USA.
d) Due to river rejuvenation when the river’s erosive activity is renewed causing the river to vigorously erode deep into its channel.
e) Where a river maintains its course across land which is being uplifted gradually.

Rapids
- A section of the rivers course where the bed is suddenly steepened causing the water to suddenly flow swiftly.
How they are formed
a) Where a less hard rock lies below a soft rock and the soft rock is eroded more resulting in a steep slope.

b) Where a water fall has been eroded by headward erosion reducing its height.

c) Where resistant rock dips downstream and is unevenly eroded.


Water Falls
- A place on a rivers course where a river bed is vertical or nearly vertical.
Formation
a) Where a river descends over a sharp edge of a plateau encountering a sharp drop.
b) Where a river descends a cliff into the sea.
c) Where a river descends a fault scarp.
d) Where a river descends a sharp edge of a plateau.
e) Where a river is blocked by lava flow causing water to accumulate on the upstream side and a water fall forms at
the point of overflow.
f) Where a resistant rock lies across a river with a less resistant one on the downstream side and the less resistant one is
eroded faster causing a rapid to be first formed, then a waterfall.
Pot Holes

- Circular depressions on a river bed.
- Form where a river flows over shallow depression and develops strong circulating currents which cause the load to
scratch the bed in circular motion.

Interlocking Spurs


- Highland projections which appear as they fit together.
Formation
- Where In the youthful stage, a river flows around spurs undercutting the outer bank more than the inner bank causing the bends to be more
pronounced making the spurs to appear as if to fit together.
The outer bank becomes river cliff/bluff and the inner bank slip off slope.